[Bldg-sim] Energyplus Schedules and Daylight Saving Time
Jim Dirkes
jim at buildingperformanceteam.com
Tue Oct 15 11:42:32 PDT 2013
Ryan,
How about setting Daylight Savings to OFF, then build your operation schedules to (manually) offset during DST?
From: Ryan Tanner [mailto:ryanatanner at gmail.com]
Sent: Tuesday, October 15, 2013 2:40 PM
To: Jim Dirkes
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Energyplus Schedules and Daylight Saving Time
Hi Jim,
For my controls investigations, it makes a difference every day during the DST period, specifically I'm optimizing window open/close schedules for natural ventilation - and when the windows open at hour 24 instead of hour 1, on a given day (say, on a day x it's a good idea to open windows at hour 1, and a bad idea to open them at hour 24) it really screws with my results.
For a generic repeating schedule, i agree that it doesn't make much difference in an annual simulation, but i'm looking at specific days, and sometimes using actual weather data - so it really is important that i get the controls implemented on the right day, at the right time.
Thanks for your help,
Ryan
On Tue, Oct 15, 2013 at 12:30 PM, Jim Dirkes <jim at buildingperformanceteam.com<mailto:jim at buildingperformanceteam.com>> wrote:
Ryan,
The E+ "hour" value is the hour preceding the value. e.g., Hour 1 is 00:01 - 1:00
That means if you move everything back one hour, what previously was 00:01 - 01:00 becomes 23:01 - 24:00. It should not be the same day, but does it make an important difference for two hours out of the year?
From: bldg-sim-bounces at lists.onebuilding.org<mailto:bldg-sim-bounces at lists.onebuilding.org> [mailto:bldg-sim-bounces at lists.onebuilding.org<mailto:bldg-sim-bounces at lists.onebuilding.org>] On Behalf Of Ryan Tanner
Sent: Tuesday, October 15, 2013 2:24 PM
To: bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>
Subject: [Bldg-sim] Energyplus Schedules and Daylight Saving Time
Greetings,
Can someone explain to me why energyplus behaves the way that it does when daylight saving time is used?
Specifically, scheduled values are shifted in the following way:
In a simulation, during DST, (summer), a schedule with 24 unique values for a single day will have values [2:24] used during hours 1:23, and value [1] used during hour 24. The first part seems reasonable, shift scheduled values back by one hour, but the last part seems wrong, shifting a scheduled value from hour 1 to hour 24 of the same day.
Since I'm doing controls studies, and I use schedules to define when some systems are on or off, this issue is particularly troubling. When I intend for a system to be ON during hour 1 and OFF during hour 2, the schedule is adjusted by energyplus so that during the simulation the system is OFF during hour 1, and ON during hour 24...not exactly what I intended.
Have any other users experienced this? Any suggestions for a workaround? I would like to have DST in effect, so that occupancy, lighting schedules, equipment schedules, etc. are correct relative to the sun's position and the local weather conditions - and I would ALSO like for my controls schedules to be used as intended, not shifted forward or backward, so that when I schedule a system to be ON during hour 1, it is ON during hour 1, whether it's winter or summer in simulation.
An example file and complete results are attached; file description and results sample are included below.
Cheers,
Ryan
----
I've attached an example IDF that demonstrates the issue, as well as the CSV output, my file is adapted from the example file: 1ZoneUncontrolledResLayers.idf; I made the following changes:
1. added a RUNPERIODCONTROL:DAYLIGHTSAVINGTIME object that applies DST from March 5 to November 5
2. added a schedule:compact object called DST_test_schedule
**this schedule has the following format, each hour for each day has a unique value which should match that day and time; so the value for March 2, hour 5 is 3.0205, the value for March 4, hour 7 is 3.0407, etc.
3. added an output for the above schedule, removed all other outputs
4. removed annual runperiod, added two shorter runperiods that encompass the DST start and end dates.
In the InputOutputReference, the following note is provided:
----
Note: For EnergyPlus Output:Variable and Output:Meter reporting, the time stamps are always in standard time. When daylight saving time is active, scheduled loads and controls will shift one hour relative to standard time.
----
**this is not accurate, since MOST values are shifted (backward) by 1 hour, but values scheduled during hour 1 are shifted (forward) by 23 hours.
--excerpt from results CSV--
Date/Time, DST_TEST_SCHEDULE:Schedule Value [](Hourly)
...
...
...
03/03 22:00:00, 3.0322
03/03 23:00:00, 3.0323
03/03 24:00:00, 3.0324
03/04 01:00:00, 3.0401
03/04 02:00:00, 3.0402
03/04 03:00:00, 3.0403
03/04 04:00:00, 3.0404
03/04 05:00:00, 3.0405
03/04 06:00:00, 3.0406
03/04 07:00:00, 3.0407
03/04 08:00:00, 3.0408
03/04 09:00:00, 3.0409
03/04 10:00:00, 3.041
03/04 11:00:00, 3.0411
03/04 12:00:00, 3.0412
03/04 13:00:00, 3.0413
03/04 14:00:00, 3.0414
03/04 15:00:00, 3.0415
03/04 16:00:00, 3.0416
03/04 17:00:00, 3.0417
03/04 18:00:00, 3.0418
03/04 19:00:00, 3.0419
03/04 20:00:00, 3.042
03/04 21:00:00, 3.0421
03/04 22:00:00, 3.0422
03/04 23:00:00, 3.0423
03/04 24:00:00, 3.0424
03/05 01:00:00, 3.0502
03/05 02:00:00, 3.0503
03/05 03:00:00, 3.0504
03/05 04:00:00, 3.0505
03/05 05:00:00, 3.0506
03/05 06:00:00, 3.0507
03/05 07:00:00, 3.0508
03/05 08:00:00, 3.0509
03/05 09:00:00, 3.051
03/05 10:00:00, 3.0511
03/05 11:00:00, 3.0512
03/05 12:00:00, 3.0513
03/05 13:00:00, 3.0514
03/05 14:00:00, 3.0515
03/05 15:00:00, 3.0516
03/05 16:00:00, 3.0517
03/05 17:00:00, 3.0518
03/05 18:00:00, 3.0519
03/05 19:00:00, 3.052
03/05 20:00:00, 3.0521
03/05 21:00:00, 3.0522
03/05 22:00:00, 3.0523
03/05 23:00:00, 3.0524
03/05 24:00:00, 3.0501
03/06 01:00:00, 3.0602
03/06 02:00:00, 3.0603
03/06 03:00:00, 3.0604
...
...
...
--
cell.401.932.6121
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